Passerine Birds 257 
Colorado Springs July 25th, 1897, and there is an example in the Carter 
collection taken at Breckenridge, June 30th, 1882. 
ORDER PASSERES. : 
This group embodies the ordinary perching birds and 
contains over 6,000 species—as many as all the other orders 
put together. It is by no means an easy order to diagnose 
by external characters, but the following apply, at any 
rate, to all North American forms: Bill of variable 
shape and size, but never with a soft or tumid cere at 
the base ; wing with nine or ten primaries, if the latter 
the outer one usually very distinctly shorter than the 
others ; secondaries always more than six ; tail of varying 
size and shape, but always of twelve rectrices; feet 
with four toes, the first or hallux directed backwards, 
not reversible, and always jointed at the same level as 
the others ; oil-gland naked ; young hatched naked and 
helpless. 
Key OF THE FamMILizs. 
A. Tarsus rounded behind; sides and back of the tarsus covered 
with variously arranged scutes, with a ‘‘ seam” along the 
inner side. 
a. Ten primaries, the outer the longest; hind toe longer than 
its claw, which is curved. Tyrannide, p. 259, 
b. Only nine primaries, the outer (tenth) obsolete; hind claw 
straight and longer than its toe. Alaudide, p. 279. 
B. Tarsus covered postero-laterally with two entire longitudinal 
plates, meeting posteriorly to form a sharp ridge. 
a. Primaries apparently only nine, the outer (tenth) rudimentary 
or obsolete, not obvious. 
at Outer primaries twice as long as the inner ones ; bill short; 
broad, flat, notched and deeply cleft. 
Hirundinide, p, 412. 
b! Outer primaries not twice the inner ones. 
a? Bill slender and thin at base. 
a? Head crested, outer (tenth) primary present, but so 
short as readily to escape notice. 
Bombycillide, p. 424, 
s 
